Just about every character in Mrs Dalloway feels isolated in some way. Although many of them are bound by tradition, class, history, love of empire, or survival of trauma, they still feel very alone in the world. Woolf uses metaphors of thread and fish swimming in water to indicate how loose the connections between people are. People see each other as objects, not as subjects; they think about others but don’t necessarily communicate with them – even though they’re desperate to. Characters seem to lack the right language to have meaningful exchanges. Clarissa's husband, who loves her very much, finds himself incapable of even saying "I love you," and must use flowers to send the message. Clarissa’s parties aim to bring people together but really become gatherings of a bunch of isolated individuals. The isolation that people feel throughout Mrs Dalloway brings with it deep feelings of fear – that the entire world is against them. In the end, Clarissa feels more of a connection to Septimus and the old lady across the way than to anyone else.
Many of the characters in the novel are isolated, but it’s not always clear what they’re isolated from.
Clarissa's isolation is nothing compared to the isolation felt by Septimus.